Hot on the heels of Titan and Enceladus, Dione is another Saturnian moon believed to hold subterranean water. The exciting news was revealed by the Royal Observatory of Belgium who by using a combination of flybys made by the Cassini spacecraft and computer modelling, successfully measured the gravity data of the moon. The results found that Dione’s crust is in fact floating above a 100km long subterranean ocean. Tens of kilometres deep, this space sea surrounds the moon’s icy core. It is yet to be 100 per cent confirmed but if it’s true, Dione will be the third of Saturn’s moons to hold water and the seventh humans have found in the solar system.

The moon Dione as seen from the Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute

The interior of Enceladus is similar to what experts think Dione has: an icy crust with an underground ocean surrounding a solid core. Credit: NASA/JPL

The images were originally found by Cassini, which scoured the Saturnian system for 12 years. Credit: NASA/JPL

So, what does this all mean? Well, locating water on planets and moons within our solar system is one of the first ways to deduce whether it could possibly be habitable in the future. Dione’s ocean could potentially hold microbial life and the relationship between the moon’s core and the ocean could harness potential energy as well as minerals and nutrients. Unlike Enceladus, Dione’s ocean is too deeply embedded to eject water into space. This makes any more in-depth analysis tough but in the future it is not out of the question that a hopper could be constructed that could land on Dione, providing a much closer inspection. Buoyed by this success, future missions will be sent even further afield to Uranus and Neptune in the hope of finding more of these water worlds.